1. Field of the Invention
The invention relates to RF plasma producing apparatus used in etching or deposition processes and in particular to apparatus and methods for the monitoring and control of such plasma producing apparatus.
2. Description of the Prior Art
Present RF plasma technology maintains a constant indicated forward power at the RF source, regardless of mismatch reflections, transmission line losses, nonrepeatable impedance matching losses, reactor feed losses and RF envelope modulation due to plasma load nonlinearities interacting with power source instabilities. Process diagnostics is often reduced to a guessing game once gas flow and pressure controls are checked against each other. One use of RF plasmas is the etching of semiconductor materials to define circuit parameters in the electronics industry.